This invention relates to a universal, or generic system for environmental stressing and screening of electronic devices such as circuit boards. The devices are placed in a stressing chamber where the temperatures are cycled between high and low limits, while at the same time, the power supplied to the devices is being cycled on and off. This temperature and power cycling stresses and serves to weed out weak components prior to failure in the field.
In prior systems, the process of stressing (or burn in) was performed on a prototype of the device, but as the need for improved reliability increased, it has become common practice to perform stress screening on every component. As a result, the stressing chamber has become very large, and is essentially a walk in room. The carts used to hold the equipment have also become large and complicated, and each cart is custom designed for the particular devices being stressed.
The use of large customized systems is satisfactory for high volume manufacture, but in many high technology applications, products are built in small quantities, and custom design is not economically feasible.
In the prior art systems, every new product required a customized cart to fit the product size, configuration and electrical connection requirements. Therefore, in low quantity manufacture, such tests were either not performed, or the cost of stressing was a very significant factor. In accordance with this invention, 100% environmental stress screening is made economically feasible because the new system allows reconfiguration of the cart for a wide variety of products with minimum requirements for customization.